Waterjet Pump Speed Control for Cutting Pattern Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Water jet cutting systems with plunger pumps face pressure fluctuations that disrupt the cutting pattern, particularly during restarts, as the high-pressure pump needs to accelerate from standstill for each new cutting process, leading to inconsistent cutting performance, especially when starting within a workpiece surface rather than from an edge.
Innovation Solution
Implementing a servo motor with a servo converter for the high-pressure pump, controlled by a setpoint generator and controller, allows for rapid acceleration and deceleration of the pump, maintaining pressure in the high-pressure line during shutdown and restart, eliminating the need for a return line and ensuring consistent pressure for immediate cutting resumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the high-pressure pump is accelerated from standstill for each new cutting process, then the cutting process can be restarted, but the pressure builds up gradually causing changes in the cutting pattern
Solution Approach 1:
The pump is kept running at reduced speed during the cutting pause, maintaining pressure in the high-pressure line without delivering water. This preliminary action ensures that when the cutting process resumes, the required pressure is already present, eliminating the need to accelerate from standstill and ensuring consistent cutting pattern from the start.
Solution Approach 2:
The pump speed is dynamically adjusted during operation - reduced to a lower speed during cutting pauses to maintain pressure without water delivery, and quickly accelerated when cutting resumes. This dynamic control allows the system to adapt between different operational states while maintaining cutting consistency.
2Loss of energy
If the high-pressure pump is shut down completely during cutting pause, then energy is saved, but the pump must be restarted from standstill causing pressure fluctuations
Solution Approach 1:
The pump is kept running at reduced speed during the cutting pause, maintaining pressure in the high-pressure line without delivering water. This preliminary action ensures that when the cutting process resumes, the required pressure is already present, eliminating the need to accelerate from standstill and ensuring consistent cutting pattern from the start.
3Loss of substance
If a return line is used to return water to the water tank, then water is recycled, but the system complexity increases and pressure control becomes more difficult
Solution Approach 1:
The invention extracts and eliminates the return line from the system. By keeping the pump running during cutting pauses and using a valve to block water delivery while maintaining pressure, the system avoids the need for water recycling infrastructure, simplifying the overall system structure while maintaining cutting consistency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures a uniform cutting pattern from the start of each cutting process by maintaining and rapidly re-establishing the required water pressure, reducing pressure fluctuations and eliminating the need for a return line, thereby improving cutting consistency and efficiency.
Implementation Method 1
The water sucked in by the high-pressure pump from a water tank is fed through a high-pressure line to the cutting head at the set pressure, depending on the cutting conditions, for example between 500 and 4000 bar, where it is pumped through a pure water nozzle at a speed of up to 800 m/s
Implementation Method 2
the cutting head valve is opened, as well as to a suitable water jet cutting system... the cutting head valve is opened... the high-pressure pump is shut down while the cutting head valve is closing while the pressure in the high-pressure line is being maintained
Implementation Method 3
the drive of the high-pressure pump includes a servo motor with a servo converter that can be switched depending on the actuation of the cutting head valve, and that, to control the servo converter, a setpoint generator and on the other hand, a controller connected to an actual value transmitter for the pressure in the high-pressure line is provided
Implementation Method 4
a controller connected to an actual value transmitter for the pressure in the high-pressure line is provided
Data Source
Figure 1
AI summary
A method for operating a waterjet cutting system is described, comprising a high-pressure pump (1) with several immersion pistons (2) connected to a water tank (5) and a high-pressure line (7) connected to the high-pressure pump (1) and to a cutting head (8) via a cutting head valve (11). During the cutting process, the high-pressure pump (1) is driven and the cutting head valve (11) is opened. To create advantageous cutting conditions at the beginning of a cutting process, it is proposed that at the end of the cutting process, the high-pressure pump (1) be switched off while the cutting head valve (11) is closing, while maintaining pressure in the high-pressure line (8), and restarted at the beginning of the cutting process while the cutting head valve (11) is opening.